/*******************************************************************************
    Copyright (c) 2014 IBM Corp.

    All rights reserved. This program and the accompanying materials
    are made available under the terms of the Eclipse Public License v1.0
    and Eclipse Distribution License v1.0 which accompany this distribution.

    The Eclipse Public License is available at
      http://www.eclipse.org/legal/epl-v10.html
    and the Eclipse Distribution License is available at
     http://www.eclipse.org/org/documents/edl-v10.php.

    Contributors:
      Ian Craggs - initial API and implementation and/or initial documentation
 *******************************************************************************/

#include "MQTTPacket.h"
#include "StackTrace.h"

#include <string.h>


/**
    Deserializes the supplied (wire) buffer into subscribe data
    @param dup integer returned - the MQTT dup flag
    @param packetid integer returned - the MQTT packet identifier
    @param maxcount - the maximum number of members allowed in the topicFilters and requestedQoSs arrays
    @param count - number of members in the topicFilters and requestedQoSs arrays
    @param topicFilters - array of topic filter names
    @param requestedQoSs - array of requested QoS
    @param buf the raw buffer data, of the correct length determined by the remaining length field
    @param buflen the length in bytes of the data in the supplied buffer
    @return the length of the serialized data.  <= 0 indicates error
*/
int MQTTDeserialize_subscribe(unsigned char* dup, unsigned short* packetid, int maxcount, int* count, MQTTString topicFilters[],
                              int requestedQoSs[], unsigned char* buf, int buflen) {
    MQTTHeader header = {0};
    unsigned char* curdata = buf;
    unsigned char* enddata = NULL;
    int rc = -1;
    int mylen = 0;

    FUNC_ENTRY;
    header.byte = readChar(&curdata);
    if (header.bits.type != SUBSCRIBE) {
        goto exit;
    }
    *dup = header.bits.dup;

    curdata += (rc = MQTTPacket_decodeBuf(curdata, &mylen)); /* read remaining length */
    enddata = curdata + mylen;

    *packetid = readInt(&curdata);

    *count = 0;
    while (curdata < enddata) {
        if (!readMQTTLenString(&topicFilters[*count], &curdata, enddata)) {
            goto exit;
        }
        if (curdata >= enddata) { /* do we have enough data to read the req_qos version byte? */
            goto exit;
        }
        requestedQoSs[*count] = readChar(&curdata);
        (*count)++;
    }

    rc = 1;
exit:
    FUNC_EXIT_RC(rc);
    return rc;
}


/**
    Serializes the supplied suback data into the supplied buffer, ready for sending
    @param buf the buffer into which the packet will be serialized
    @param buflen the length in bytes of the supplied buffer
    @param packetid integer - the MQTT packet identifier
    @param count - number of members in the grantedQoSs array
    @param grantedQoSs - array of granted QoS
    @return the length of the serialized data.  <= 0 indicates error
*/
int MQTTSerialize_suback(unsigned char* buf, int buflen, unsigned short packetid, int count, int* grantedQoSs) {
    MQTTHeader header = {0};
    int rc = -1;
    unsigned char *ptr = buf;
    int i;

    FUNC_ENTRY;
    if (buflen < 2 + count) {
        rc = MQTTPACKET_BUFFER_TOO_SHORT;
        goto exit;
    }
    header.byte = 0;
    header.bits.type = SUBACK;
    writeChar(&ptr, header.byte); /* write header */

    ptr += MQTTPacket_encode(ptr, 2 + count); /* write remaining length */

    writeInt(&ptr, packetid);

    for (i = 0; i < count; ++i) {
        writeChar(&ptr, grantedQoSs[i]);
    }

    rc = ptr - buf;
exit:
    FUNC_EXIT_RC(rc);
    return rc;
}


